iPod Touch "pouch" bad?

[micgao]

Hey y'all
I recently bought one of these http://store.apple-touch.com/content/accessories/4-193--5337.htm
and I realized after I put my iPod in there for a while (it stays in my pocket), my iPod feels really hot and I've heard that it is bad for the battery and the iPod. I was just wondering if it is bad or is it normal and OK to use?
Thanks
BTW my iPod is not closed but "sleeping"

[Masmo]

I suppose it does act like an insulator and keeps the heat in, especially when left under the sun or left in a hot room. It might damage your iPod overtime, although it shouldn't get hot if your iPod is sleeping and left in a cool area.